Abstract: A seven-segment display provides a set of eight lamps for each category of a test sample (such as bacteria) to be identified by the device. Manually operated electrical switches are used to enter and store the results of a plurality of tests (such as biological tests) into the device. Logic circuitry responds to the positions of the switch to control the lighting of individual lamps in the sets for the categories which have a significant positive correlation to the results entered by the switches. The display for which the greatest number of lamps in the most significant positions are lighted represents the category of the test sample being tested.